MW3 arrived in the shops on Tuesday, and after 24 hours on sale, 6.5m copies had been sold in the UK and North America.

EA's Battlefield 3 took a week to reach 5m units. EA and Activision have been sniping at each other for the past few months, each trying to position their respective games as the best modern war first-person shooter.

MW3's sales revenues eclipse those of the previous installment in the Call of Duty series, Black Ops, which yielded day-one sales of $390m.